Diagnosing Diseases

With Florida's humid, hot climate, fungus is the cause of most plant diseases, but bacteria and viruses can hurt plants as well. To diagnose a plant disease, you need to know the terminology. For example, a spot on a leaf is called a "leaf lesion," and as multiple spots grow together the symptom is called a "blight." Be sure to know what you're dealing with before attempting to treat a diseased plant—one pathogen may not react to a "cure" like another. If you're not sure, seek the help of your local Extension office.